[whatwg] BC AD BCE CE trivia

timeless timeless at gmail.com
Wed Aug 29 10:16:10 PDT 2007

On 8/29/07, WeBMartians <webmartians at verizon.net> wrote:
> There is a disagreement between astronomers and historians about how to count the years preceding year one; astronomers count the BC
> years astronomically. Thus, the year before the year 1 is the year 0, and the year preceding the latter is the year -1 (2 BC, 1 BC,
> and one are, astronomically, -1, 0, and 1, respectively). The year which the historians call 585 BC is actually the year -584. The
> astronomical counting of the negative years is the only one suitable for arithmetical purpose. For example, in the historical
> practice of counting, the rule of divisibility by 4 revealing the Julian leap-years is no longer valid; these years are, 1 BC, 5 BC,
> 9 BC, 13 BC... In the astronomical sequence, however, these leap-years are called 0, -4, -8, -12..., and the rule of divisibility by
> four subsists. In this system we can speak, for instance, of the solar eclipse of -1203-08-28 (twenty-eighth day of August in the
> year 1204 BC), although at that remote time the Roman Empire was not yet founded and the month of August was still to be conceived!

I must have missed something. But the calendar changed somewhere
around 1500, which means the leap year calculations can't simply be
done in any way like this.
http://en.wikipedia.org/wiki/Julian_calendar#New_Year.27s_Day (my
personal favorite)


> Also, the (politically?) correct way to specify BC is "Before Common Era", while AD (Anno Domini) is now CE (Common Era).


Yes, I would hope not to see AD/BC standardized somewhere.

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